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Koleksiyondaki öğeler
- MakaleYalnız künye2006Scopus SJRQ1Mineralogy, petrography and whole-rock geochemistry of the Tertiary granitic intrusions in the Eastern Pontides, Turkey
Arslan, M.; Aslan, Z.
Granitic intrusions in Eocene and post-Eocene volcanic rocks outcrop in the Northern and Southern Zones of the Eastern Pontides, NE Turkey. Intrusions in the Northern Zone extend NW-SE whereas those in the Southern Zone are nearly E-W orientated. The contacts of the intrusions with the volcanic rocks are sharp, epidotized and include volcanic xenoliths. The margins of Southern Zone intrusions often contain abundant angular mafic microgranular enclaves of diorite to quartz diorite composition. The rocks also show evidence of mingling and mixing between coeval mafic and felsic magmas. Field observations suggest a stopping type of ascent and emplacement style for the intrusions. Petrographically, intrusions show variations in both colour and mineralogy with fine to medium granular, monzonitic, poikilitic, rapakivi, anti-rapakivi and graphic textures. Based on modal mineralogy, the Northern rocks are monzonite, quartz monzonite, monzodiorite and quartz monzodiorite whereas the Southern samples are monzogranite and granodiorite. The rocks are generally calc-alkaline to mildly alkaline transitional and metaluminous, and show a CAFEMIC trend. The Northern Zone intrusions form a post-collisional, A-type, alkaline monzonitic association and Southern Zone intrusions form a post-collisional, I-type, granodioritic calc-alkaline-transitional association. Whole-rock compositional data indicate that differentiation occurred via fractional crystallisation with or without magma mixing. Incompatible and rare earth element patterns indicate that both the Northern and the Southern Zone intrusions were derived from melting of a mantle region enriched by subduction-related fluids but evolved differently during ascent and emplacement. U-Pb zircon dating in the Southern Zone yields an intrusion age of 44.4±0.3 Ma. Regional geodynamics indicates post-collisional extensional tectonics in the region. Crustal involvement and the level of emplacement may have been important for magmatic evolution, especially for the Southern Zone intrusions, after the cessation of subduction and subsequent crustal thickening.
AtıfScopus171WoS154OpenAlex160
İncele - MakaleYalnız künye2009Scopus SJRQ3Effects of nitrogen and phosphorus fertilization and seeding patterns on chemical composition of Lucerne and smooth brome grass intercropping system
Yolcu, Halil; Serin, Yunus
Intercropping has been used widely in forage plant production all around the world. In intercropping systems, forage plants need different requirements are grown together. Requirement of fertilization and seeding pattern of intercropping differ from mono cropping. The research goals were to evaluate the effects of various seeding patterns and fertilization on the crude protein and chemical content of lucerne-smooth brome grass mixture under field conditions in 2002-2003. Lucerne and smooth bromegrass mixtures were established with different seeding patterns (mixed, alternative and cross-seeding), N fertilizer rates (0, 60 and 120 kg N ha-1) and P fertilizer rates (0, 40, 80 and 120 P2O5 ha-1). The results of this study indicated that different seeding patterns, N and P fertilization affected chemical contents of alfalfa and smooth brome grass mixture in the intercropping system. Depending on different seeding patterns, N, Ca, K and Mg content varied significantly, but no P content in the intercropping system. Nitrogen application increased N content and P application likewise increased P content. While P application increased N content, N application had no effect on the P content of the intercropping. Calcium and K did not vary significantly depending on N and P fertilization; yet, a relationship between P application and Mg content was determined.
AtıfScopus7WoS7İncele - MakaleAçık Erişim2006Scopus SJRQ1A mantle- and a lower crust-derived bimodal suite in the Yusufeli (Artvin) area, NE Turkey: Trace element and REE evidence for subduction-related rift origin of Early Jurassic Demirkent intrusive complex
Dokuz, Abdurrahman; Tanyolu, Erkan; Genç, Salim
The Yusufeli area, in the Eastern Black Sea Region of Turkey, contains a crystalline complex that intruded into the Carboniferous metamorphic basement and is composed of two intrusive bodies: A gabbro-diorite and a tonalite-trondhjemite. The mafic body (45-57 wt% SiO2) displays a broad lithological spectrum ranging from plagioclase-cumulate to quartz diorite. Primitive varieties of the body have Mg-number, MgO and Cr contents that are close to those expected for partial melts from mantle peridotite. Data are consistent with the magma generation in an underlying mantle wedge that was depleted in Zr, Nb and Ti, and enriched in large ion lithophile elements (K, Rb, Ba, Th). However, high Al2O3, CaO and generally low Ni (<65 ppm) contents are not in agreement with the unfractionated mantle-derived primitive magmas and require some Al2O3- and CaO-poor mafic phases, in particular, olivine and orthopyroxene. Absence of orthopyroxene in crystallization sequence, uralitization, and a common appearance of clinopyroxene surrounded by hornblende imply an anhydrous phase fractionated from highly hydrous (5-6%) parent. Geochemical modelling suggests derivation by 15-20% melting of a depleted-lherzolitic mantle. The tonalite-trondhjemite body (58-76 wt% SiO2) ranges in composition from quartz diorite to granodiorite with a low-K calc-alkaline trend. Although LILE- and LREE- enriched characteristics of the primitive samples imply a metasomatic sub-arc mantle for their source region, low MgO, Ni and Cr concentrations rule out direct derivation from the mantle wedge. Also, lack of negative Eu anomalies suggests an unfractionated magma and precludes a differentiation from the diorites of mafic body, which show negative Eu anomalies. Their Na enrichments relative to Ca and K are similar to those of Archean tonalites, trondhjemites and granodiorites and Cenozoic adakites. However, they exhibit important geochemical differences from them, including low-Al (<15 wt%) contents, unfractionated HREE patterns and evolution towards the higher Y concentrations and lower Sr/Y ratios within the body. All these features are obtained in experimentally produced melts from mafic rocks at low pressures (≤5 kbar) and also widespread in the rocks of arc where old (Upper Cretaceous or older) oceanic crust is being subducted. Major and REE modelling supports formation of the quartz dioritic parent to the felsic intrusive rocks by 70% partial melting of a primitive gabbroic sample (G694). Therefore, once taking into account the extensional conditions prevailing in the Pontian arc crust in Early Jurassic time, former basic products (gabbros) seem to be the most appropriate source for the tonalite-trondhjemite body. Magmatic emplacement of stratigraphically similar lithologies in the Pulur Massif, just southwest of the Yusufeli, was dated to be 184 Ma by the 40Ar/ 39Ar method on amphibole, and is compatible with the initiation of Early Jurassic rifting in the region.
AtıfScopus76OpenAlex73İncele - MakaleYalnız künye2008Scopus SJRQ1Petrogenesis of the Neogene alkaline volcanics with implications for post-collisional lithospheric thinning of the Eastern Pontides, NE Turkey
Aydin, Faruk; Karsli, Orhan; Chen, Bin
Whole-rock geochemistry, Sr-Nd-Pb isotopes and K-Ar data are reported for alkaline samples collected from the Neogene alkaline volcanics (NAVs) in the Eastern Pontides, northeastern Turkey, in order to investigate their source and petrogenesis and geodynamic evaluation of the region. The NAVs were made of three groups that comprise of basanite-tephrite (feldspar-free; Group A), tephrite-tephriphonolite (feldspar and feldspathoid-bearing; Group B) and alkaline basalt-rhyolite (feldspathoid-free; Group C) series. These rocks cover a broad compositional range from silica-undersaturated to silica-oversaturated types, almost all of which are potassic in character. They show enrichment of LREE and LILE and depletion of HFSE, without a Eu anomaly in most of the mafic samples. Textural features and calculated pressures based on the Cpx-barometer in each series indicate that the alkaline magma equilibrated at shallow crustal depths under a pressure of about 3-4.5 kbar and approximating a crystallization depth of 9-14 km. The NAVs are slightly depleted in isotopic composition, with respect to 87Sr/86Sr (ranging from 0.705018 to 0.705643) and 143Nd/144Nd (ranging from 0.512662 to 0.512714) that indicate young Nd model ages (0.51-059 Ga). This may indicate that the parent melts tapped a homogeneous and young lithospheric mantle source which was metasomatized by subduction-derived sediments during the Late Mesozoic. Pb isotopic compositions (206Pb/204Pb = 18.85-18.95; 207Pb/204Pb = 15.60-15.74; 208Pb/204Pb = 38.82-39.25) may also be consistent with a model for an enriched subcontinental lithospheric mantle source. Lithospheric thinning and resultant upwelling of asthenosphere induced by lithospheric delamination may have favoured partial melting of chemically enriched, young lithospheric mantle beneath the Eastern Pontides. Then, the melt subsequently underwent a fractional crystallization process along with or without minor amounts of crustal assimilation, generating a wide variety of rock types in a post-collision extensional regime in the Eastern Pontides during the Neogene.
AtıfScopus131OpenAlex137İncele - MakaleAçık Erişim2009Scopus SJRQ3Homotopy perturbation method for solving human T-Cell lymphotropic virus I(HTLV-I) infection of CD4+ T-Cells model
Merdan, Mehmet
In this article, homotopy perturbation method is implemented to give approximate and analytical solutions of nonlinear ordinary differential equation systems such as human T-cell lymphotropic virus I (HTLV-I) infection of CD4+ T-cells model. The proposed scheme is based on homotopy perturbation method (HPM), Laplace transform and Padé approximants. The results to get the homotopy perturbation method (HPM) is applied Padé approximants. Our proposed approach showed results to analytical solutions of nonlinear ordinary differential equation systems. Some plots arepresented to show the reliability and simplicity of the methods.
AtıfScopus3OpenAlex3İncele - MakaleAçık Erişim2009Scopus SJRQ2Water quality modeling and dissolved oxygen balance in streams: A point source Streeter-Phelps application in the case of the Harsit stream
Nas, S. Serkan; Nas, Evin
The Harsit Stream flowing into the Black Sea is an important watershed in the northeastern part of Turkey. The monthly averages of dissolved oxygen, carbonaceous biochemical oxygen demand, temperature, pH, total suspended solids, total phosphorus and total nitrogen were obtained for the water samples taken from the Tekke, Akcakale and Haciemin sites of the Harsit Stream. Water quality parameters were analyzed and evaluated according to the WHO standards and the Turkish Water Pollution Control Regulation. Initially, the variations in the dissolved oxygen profile were determined from dissolved oxygen, temperature and carbonaceous biochemical oxygen demand measurements by using the point source Streeter-Phelps equation. Critical dissolved oxygen deficit values were calculated for the monthly average from January-December 2005, which are below the limit value (4 mg L-1) excluding April (7.26 mg L-1) and May (5.98 mg L-1) in the Harsit Stream, resulting in it having second class water quality in terms of dissolved oxygen concentration, temperature, pH and biochemical oxygen demand. It is also seen that the minimum dissolved oxygen limit value (8 mg L-1), which is a desired quantity for drinking water, is under the limit value for all months in the case of the water mixture. In particular, during the summer months, the consumption speed of oxygen is greater than the production speed of oxygen with increasing temperature and decreasing discharge, and negative values (anoxia) of dissolved oxygen sag are seen. These situations call for significant precautions and treatment criteria.
AtıfScopus27WoS24OpenAlex28İncele - MakaleYalnız künye2010Scopus SJRQ3Liquefaction of cotton stalks (Gossypium hirsutuml.) with phenol
Fidan, M.Said; Alma, M.Hakki; Bektas, Ibrahim
In this study, we aimed to synthesize resol type wood adhesive from resinification of cotton stalk liquefied into phenol in the presence of sulfuric acid as catalyst. The biomass was first liquefied with phenol in the presence of sulfuric acid as a catalyst at various reaction conditions. It was detected that increasing acid concentration, temperature and time resulted in a great decrease on the amount of unliquefied cotton stalks and a significant increase in the percentage of combined phenol in the produced resin. It was also found out that the resin produced from cotton stalks can be perfectly used in the production of wood composite materials.
AtıfScopus9WoS7İncele - MakaleAçık Erişim2013Scopus SJRQ1Numerical solution of the fractional-order Vallis systems using multi-step differential transformation method
Merdan, Mehmet
In this paper, we examine a fractional order Vallis systems. We also fulfil a detailed analysis on the stability of equilibrium. Multi-step differential transform method (MsDTM) extends to give approximate and analytical solutions of a fractional order Vallis systems. Numerical simulations are submitted to verify the validity and reliability results obtained from these methods.
AtıfScopus10WoS10OpenAlex9İncele - MakaleAçık Erişim2014Scopus SJRQ2Assessment of kinetics, thermodynamics, and equilibrium parameters of Cu(II) adsorption onto Rosa canina seeds
Serencam, Huseyin; Ozdes, Duygu; Duran, Celal; Senturk, Hasan Basri
Rosa canina seeds (RCS) is considered as a low-cost and promising adsorbent in removal of metal ions; hence, in the present study, we aimed to test the adsorptive removal of Cu(II) ions from aqueous solutions by utilizing RCS in a batch process. After characterization of RCS by using several techniques, the effects of various experimental parameters such as initial pH of aqueous solution, contact time, initial Cu(II) concentration, RCS concentration, temperature, and electrolyte concentration were studied upon the adsorption process. The desorption conditions of Cu(II) ions from the loaded RCS were also evaluated. Maximum Cu(II) adsorption was found to occur at pH 6.0 and the equilibrium was established after 60 min of contact time. The adsorption isotherms were described by means of Langmuir, Freundlich, Temkin, and Dubinin Radushkevich models. The adsorption kinetics were analyzed using pseudo-first-order, pseudo-second-order, Elovich and intraparticle diffusion models and the adsorption data were well described by the pseudo-second-order model. Thermodynamic parameters such as the Gibbs free energy (ΔG), enthalpy (ΔH), and entropy (ΔS) changes were also evaluated and it has been found that the adsorption process was feasible, spontaneous, and endothermic in the temperature range of 278-313 K.
AtıfScopus19WoS20OpenAlex19İncele - MakaleYalnız künye2014Scopus SJRQ1Assessment of liquefaction potential of Erzincan Province and its vicinity, Turkey
Subası Duman, E.; Ikizler, S.B.
One of the most important causes of damages after the earthquakes is the soil liquefaction. Liquefaction can be defined as temporary loss in strength of saturated sandy and silty deposits under transient and cyclic loadings due to excess pore water pressure. This study includes determination of liquefaction potential in Erzincan city center and its vicinity. Due to the proximity of the North Anatolian Fault Zone, in a probable earthquake, Erzincan Province is thought to be affected. In this context, the earthquake scenarios were produced using the empirical expressions. Liquefaction potential for different earthquake magnitudes was determined. These earthquake magnitudes were selected as 6.0, 6.5, 7.0, 7.5, respectively. Liquefaction potential was investigated using standard penetration test (SPT) data. The first stage of the study, 63 boreholes in different locations was drilled and SPT was performed. Disturbed and undisturbed soil samples were taken from these boreholes. Laboratory testing was performed to determine physical properties of soil samples, and liquefaction potential analyses were examined using three methods, namely Seed and Idriss (J Soil Mech Found Div ASCE 97(9):1249-1273, 1971), Tokimatsu and Yoshimi (Soil Found 23(4):56-74, 1983), Iwasaki et al. (Soil liquefaction potential evaluation with use of the simplified procedure. International Conference on Recent Advances in Geotechnical Earthquake Engineering and Soil Dynamics, St. Louis, pp 209-214, 1981). In order to complete liquefaction analysis within a short time, MATLAB program was prepared. Liquefaction potential analyses were carried out with the MATLAB program. At the final stage of this study, liquefaction potential maps were prepared for different earthquake magnitudes. The expected results will be shared with the local authorities and important engineering remedial measurements will be proposed to prevent further life losses and to mitigate property losses.
AtıfScopus6WoS3OpenAlex7İncele - MakaleAçık Erişim2010Scopus SJRQ1Structure and geochemistry of an Alaskan-type ultramafic-mafic complex in the Eastern Pontides, NE Turkey
Eyuboglu, Yener; Dilek, Yildirim; Bozkurt, Erdin; Bektas, Osman; Rojay, Bora; Sen, Cuneyt
The Karayasmak ultramafic-mafic association (KUMA) in NE Turkey represents an Alaskan-type, pre-Liassic intrusion in the Pulur metamorphic massif and is one of many such intrusive complexes that were emplaced into the continental basement of the Eastern Pontides belt during the pre-Liassic. Its main lithological units include plagioclase peridotite, melagabbronorite, banded gabbro and anorthosite (Phase-I), gabbro-pegmatite dikes (Phase-II), unmetamorphosed banded gabbro (Phase-III), cumulate olivine gabbronorite (Phase-IV), and non-cumulate gabbroic dikes and stocks (Phase-V). The contact relations between these units are gradational or intrusive, with the peridotites (Phase-I) enveloping the cumulate gabbronorites (Phase-IV) in the center of the elliptical body, displaying a concentric reverse-zoning pattern. Cr-Al spinel, plagioclase, and olivine are the first crystallizing phases in all cumulate rocks, whereas pyroxene, hornblende, phlogopite, magnetite, and ilmenite represent the intercumulus phases. The existence of hornblende and phlogopite, the high Wo and Cr2O3 contents of clinopyroxene, and the high Fo and NiO contents of olivine indicate that the KUMA units were the near-liquidus fractional crystallization products of hydrous basaltic magma. The Phase-I and Phase-III cumulates are slightly enriched in LILE and LREE, depleted in HFSE and HREE with respect to chondrite and primitive mantle, and show negative Nb, Zr, Hf and Ti anomalies. The Phase-IV cumulate gabbronorites are even more enriched in LILE and LREE and show less depletion in HFSE and HREE in comparison to the earlier phases. The KUMA units formed from high-Al hydrous basaltic magmas, which were derived from partial melting of a previously subduction-metasomatized subcontinental-lithospheric mantle. These magmas underwent crystal fractionation and mineral concentration processes in small magma chamber(s) at shallow crustal levels (< 5 kbar).
AtıfScopus123WoS115OpenAlex112İncele - MakaleYalnız künye2010Scopus SJRQ3Consumer perceptions of organic foods in Turkey
Ilyasoǧlu, Huri; Temel, Sara; Özçelik, Beraat
This study presents the results of a survey regarding consumer perceptions of organic foods in Turkey. The survey was conducted to determine consumer attitudes towards organic foods and the reasons for consumption or non-consumption of organic foods. A total of 383 consumers from different occupational groups living in Istanbul participated in the research. The results of the survey revealed that more than half of the survey participants had knowledge about organic foods. The majority of the participants were positive towards organic foods and purchased them as well. The results of chi-square analysis showed that the consumption of organic foods varied with respect to gender, job and education. Women and more educated participants tend to buy organic foods more than other participants. In market, fruits and vegetables, cereals and legumes, dried fruits and dairy products were organic products recognized by consumers. The main organic products purchased by consumers were fruits and vegetables. The results of the survey also indicated that the participants confidence in organic foods was at moderate level. About 37% of the participants was found to rely on organic foods and about 49% of the participants were unsure about organic foods. Organic foods were purchased because they were perceived as healthy, environmentally friendly and more nutritious than conventional foods. However, the consumption of organic foods was found to be lower. The majority of the participants stated that they consumed organic foods rarely or sometimes. Price and lack of availability of organic foods were barriers to increase the consumption of organic foods.
AtıfScopus4WoS2İncele - MakaleAçık Erişim2015Scopus SJRQ2Effects of distant Reiki on pain, anxiety and fatigue in oncology patients in Turkey: A pilot study
Demir, Melike; Can, Gulbeyaz; Kelam, Ayhan; Aydiner, Aydin
Background: Fatigue, stress and pain are common symptoms among cancer patients, affecting the quality of life. The purpose of the present study was to determine the effect of distant Reiki on pain, anxiety and fatigue in oncology patients. Materials and Methods: Participants in the control group received usual medical and nursing care during their stay. The intervention group received usual care plus five distant Reiki sessions, one each night for 30 min. A face to face interview was performed and patient personal and illness related characteristics were evaluated using the Patient Characteristics form. Pain, stress and fatigue were evaluated according to a numeric rating scale. Results: The experimental group was predominantly composed of women (71.4%), married individuals (40%), and primary school graduates (40%). The control group was predominantly male (72.7%), married (60%), and primary school graduates (60%). The control group demonstrated greater levels of pain (p=0.002), stress (p=0.001) and fatigue (p=0.001). The Reiki group pain score (p < 0.0001), stress score (p < 0.001) and fatigue score were also significantly lower. Conclusions: The results of this study indicate that Reiki may decreasepain, anxiety and fatigue in oncology patients.
AtıfScopus48OpenAlex73
İncele - MakaleYalnız künye2015Scopus SJRQ4Contributions to the knowledge of the genus Vestiferum Martens, 2006 (opiliones: Nemastomatidae) from Turkey
Kurt, Kemal
Two species of the genus Vestiferum Martens, 2006 were found in Turkey. One of them, V. funebre (Redikortsev, 1936) is found in Turkey for the first time. The other species V. alatum Martens, 2006 is recorded from a new locality in Turkey. Both species were collected from the northern part of Turkey. Their descriptions, characteristic features, distributions and digital and SEM photographs are presented.
AtıfScopus1WoS1İncele - BildiriAçık Erişim2014Scopus SJRQ3Suggestion of new formulations for schmidt hammer and UPV test methods for concrete
Cavdar, A.; Bingöl, S.
The concrete is the most widely used building material in Turkey. Especially reinforced concrete dominates at building sector. Because of concrete is an non-homogeneous and non-isotropic material, the strength of concrete cannot be accurately achieved at the site. To control the mechanical properties of concrete in the site, non- -destructive test methods can be used. They are useful for having no damage on concrete, however these test results sometimes gives deceptive results. In this study, two of non-destructive test methods, Schmidt hammer testing and ultrasonic pulse velocity methods were used for determining concrete compressive strength. 101 samples were poured concrete cube dimensions 150×150×150 mm3. On 28th days, firstly, the samples were applied Schmidt hammer test and ultrasonic pulse velocity test and then the compressive strength of these samples was measured by breaking in the press, destructive method. Thus, the new formulations are obtained for Schmidt hammer test and ultrasonic pulse velocity test.
AtıfScopus4WoS3OpenAlex3İncele - MakaleYalnız künye2010Scopus SJRQ1Generation of the Early Cenozoic adakitic volcanism by partial melting of mafic lower crust, Eastern Turkey: Implications for crustal thickening to delamination
Karsli, Orhan; Dokuz, Abdurrahman; Uysal, Ibrahim; Aydin, Faruk; Kandemir, Raif; Wijbrans, Jan
Early Cenozoic (48-50 Ma) adakitic volcanic rocks from the Eastern Pontides, NE Turkey, consist of calc-alkaline and high-K calc-alkaline andesite and dacite, with SiO2 contents ranging from 56.01 to 65.44 wt.%. This is the first time that Early Eocene volcanism and adakites have been reported from the region. The rocks are composed of plagioclase, amphibole, quartz, and Mg-rich biotite. They have high and low-Mg# values ranging from 55 to 62 and 13 to 42, respectively. High-Mg# rocks have higher Ni and Co contents than low-Mg# samples. The rocks exhibit enrichments in large ion lithophile elements including the light rare earth elements, depletions in Nb, Ta and Ti and have high La/Yb and Sr/Y ratios. Their relative high ISr (0.70474-0.70640) and low εNd (50 Ma) values (- 2.3 to 0.8) are inconsistent with an origin as partial melts of a subducted oceanic slab. Combined major- and trace element and Sr-Nd isotope data suggest that the adakitic magmas are related to the unique tectonic setting of this region, where a transition from a collision to an extension stage has created thickening and delamination of the Pontide mafic lower crust at 50 Ma. The high-Mg adakitic magmas resulted from partial melting of the delaminated eclogitic mafic lower crust that sank into the relatively hot subcrustal mantle, and its subsequent interaction with the mantle peridotite during upward transport, leaving garnet as the residual phase, elevates the MgO content and Mg# of the magmas, whereas low-Mg# magmas formed by the melting of newly exposed lower crustal rocks caused by asthenospheric upwelling, which supplies heat flux to the lower crust. The data also suggest that the mafic lower continental crust beneath the region was thickened between the Late Cretaceous and the Late Paleocene and delaminated during Late Paleocene to Early Eocene time, which coincides with the initial stage of crustal thinning caused by crustal extensional events in the Eastern Pontides and rules out the possibility of an extensional regime before ~ 50 Ma in the region during the Late Mesozoic to Early Cenozoic.
AtıfScopus257WoS238OpenAlex247İncele - MakaleYalnız künye2011Scopus SJRQ2Vibration-based operational modal analysis of the mikron historic arch bridge after restoration
Altunişika, Ahmet Can; Bayraktar, Alemdar; Sevima, Bariş; Birincia, Fatma
This research presents finite element modelling, vibration-based operational modal analysis, and finite element model updating of a restored historic arch bridge. Mikron historic bridge, constructed on Fi{dotless}rti{dotless}na River in Rize, Turkey, is the subject of this case study. The General Directorate for Highways of Turkey repaired the bridge's main structural elements, arches, sidewalls, and filler material in 1998. To construct a 3D finite element model of the bridge, ANSYS finite element software estimated the analytical dynamic characteristics. Induced ambient vibrations such as human walking and wind excited the model bridge to allow measurement of the bridge's responses. Enhanced frequency domain decomposition in frequency domain and stochastic subspace identification in time domain methodologies extracted experimental dynamic characteristics. A comparison of the analytical and experimental results showed significant agreement between mode shapes, but some differences in natural frequencies appeared. Consequently, updating the finite element model of the bridge by changing boundary conditions minimised the differences between analytical and experimental natural frequencies. After the finite element model updating process, the differences between natural frequencies declined from 7% to 2%.
AtıfScopus20WoS20OpenAlex21İncele - MakaleYalnız künye2015Scopus SJRQ4A new species and a new record of the Genus Rilaena Šilhavý, 1965 (Opiliones: Phalangiidae) from Turkey
Kurt, Kemal
Two harvestmen species were collected from Trabzon Province in Turkey. Rilaena ermani sp. n. is described as new to science, and Rilaena zakatalica Snegovaya & Chemeris, 2005 is recorded for the first time in Turkey. Detailed descriptions and illustrations of new species are provided. Differences between the new species and related species are discussed. In addition, illustrations of new record are also presented.
AtıfScopus4WoS2OpenAlex4İncele - MakaleYalnız künye2012Scopus SJRQ2Safety and effectiveness of 5-mm and 10-mm electrothermal bipolar vessel sealers (LigaSure) in laparoscopic resections for sigmoid colon and rectal cancers
Gezen, Cem; Kement, Metin; Altuntas, Yunus E.; Aksakal, Nihat; Okkabaz, Nuri; Civil, Osman; Vural, Selahattin; Oncel, Mustafa
Background: LigaSure™ (Covidien, Mansfield, MA) has been used in cases undergoing laparoscopic colon and rectal resections. This study aims to analyze the efficacy and safety of the 5-mm and 10-mm devices. Subjects and Methods: Patients who received a laparoscopic or hand-assisted laparoscopic operation for a tumor located in the sigmoid colon or rectum since 2006 were abstracted from a prospectively designed database, and findings were analyzed in two groups based on size of the device used during the procedure. The videotapes of the procedures were watched, and operation reports were read to obtain further information on specific intra- and postoperative complications. Demographics, tumor and operation-related information, and postoperative data were compared. Results: Among 215 (128 [59.5%] males; median age, 59.5±13.8 years) patients, data obtained from the 5-mm (n=32) and 10-mm (n=183) groups were identical regarding demographics and data related to tumor (localization and stage) and operation (number of harvested lymph nodes, conversion rates, operation time, intraoperative bleeding, transfusion requirement, reoperation rates, complications, 30-day mortality, and length of hospital stay). However, more patients underwent an anterior resection in the 10-mm group than in the 5-mm group (31.7% versus 15.6%, P<.05). Further analyses found device-related bleeding in 8 (3.7%) cases (2 [6.3%] versus 6 [3.3%] in the 5-mm versus 10-mm group, respectively, P>.05), requiring further attempts for hemorrhage control (n=6), conversion to open surgery (n=1), or relaparotomy (n=1). Conclusions: The 5-mm and 10-mm LigaSure devices are similarly effective and safe during laparoscopic sigmoid colon and rectal resections. Severe bleeding from larger vessels may be observed, requiring conversion to open surgery or relaparotomy.
AtıfScopus3WoS3OpenAlex3İncele - Derleme MakaleYalnız künye2014Scopus SJRQ2On the solutions of nonlinear fractional Klein-Gordon equation with modified Riemann-Liouville derivative
Merdan, Mehmet
In this paper, fractional variational iteration method (FVIM) is applied for finding approximate analytical solutions of nonlinear fractional Klein-Gordon equation. Time-fractional derivative is described in the Riemann-Liouville sense. A new application of fractional variational iteration method (FVIM) is extended to derive analytical solutions in the form of a series for this equation. The behavior of the solutions and the effects of different values of fractional order α are indicated graphically. It is shown that the solutions obtained by the FVIM are reliable, convenient and effective for strongly nonlinear partial equations with modified Riemann-Liouville derivative.
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